package org.reggie.controller;

import lombok.val;
import org.reggie.common.R;
import org.springframework.beans.factory.annotation.Value;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.PostMapping;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RestController;
import org.springframework.web.multipart.MultipartFile;

import javax.servlet.ServletOutputStream;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import java.io.File;
import java.io.FileInputStream;
import java.io.FileNotFoundException;
import java.io.IOException;
import java.util.UUID;

//文件上传和下载
@RestController
@RequestMapping ("/common")
public class CommonController {
    //@Value("${reggie.path}")
    //@Value("123123")
    @Value("${reggie.path}")
    private  String basePath;
    @PostMapping("/upload")
    public R<String> upload(MultipartFile file){
        String originalFilename=file.getOriginalFilename();
        String suffix=originalFilename.substring(originalFilename.lastIndexOf("."));
        //使用UUID重新生成文件名，防止文件名称重复造成文件覆盖
        String fileName= UUID.randomUUID().toString()+suffix;
        //创建一个目录对象
        File dir=new File(basePath);
        if(!dir.exists()){
            dir.mkdirs();
        }
        //当前file是一个临时文件，需要转存到指定位置，否则下次请求完成后临时文件会删除
        try{
            //将临时文件转存到指定位置
            file.transferTo(new File(basePath+fileName));
        }catch (IOException e){
            e.printStackTrace();
        }
        return R.success(fileName);
    }
    //文件下载为什么用HttpServletResponse 输入输出流代表响应
    @GetMapping("/download")
    public void download(String name, HttpServletResponse response){
        //输入流，通过输入流读取文件
        try {
            FileInputStream fileInputStream = new FileInputStream(new File(basePath+name));
            //输出流，通过输出流将文件写回浏览器，在浏览器展示图片
            ServletOutputStream outputStream = response.getOutputStream();
            int len=0;
            byte[]bytes=new byte[1024];
            while((len=fileInputStream.read(bytes))!=-1){
                 outputStream.write(bytes,0,len);
                 outputStream.flush();
            }
            outputStream.close();
            fileInputStream.close();
        } catch (Exception e) {
            e.printStackTrace();
        }
    }

}
